Conventional laundering techniques for the cleaning and treatment of fabric articles such as garments have long involved both traditional aqueous based washing and a technique commonly referred to as “dry cleaning”. Traditional aqueous based washing techniques have involved immersion of the fabric articles in a solution of water and detergent or soap products followed by rinsing and drying. However, such conventional immersion cleaning techniques have proven unsatisfactory on a wide range fabric articles that require special handling and/or cleaning methods due to a fabric content, construction, etceteras, that is unsuitable for immersion in water.
Accordingly, the use of the laundering method of “dry cleaning” has been developed. Dry cleaning typically involves the use of non-aqueous, lipophilic fluids as the solvent or solution for cleaning. In this manner, fabrics that are incompatible with water immersion may be cleaned and treated without the potential disastrous side effects water may present.
While a broad range of non-aqueous lipophilic fluids are available, many require the presence of low levels of water in the form of emulsions or microemulsions to maximize cleaning efficiency without sacrificing the “safety” accorded fabrics via dry cleaning. In addition, it is desirable to re-cycle and/or purify these non-aqueous, lipophilic fluids to reduce the much higher operating cost associated with dry cleaning as opposed to its aqueous based cousin. However, prior to purifying the lipophilic fluid, it is desirable to separate water from the emulsion prior to some of the lipophilic purification steps. Thus, a cost-effective, efficient, and safe way to separate water from these emulsions is desired, particularly when adjuncts such as emulsifiers are utilized.
U.S. Pat. Nos. 4,555,344, 4,828,710, and European Application EP 648,521 A2 disclose the use of absorptive materials to separate low molecular weight solvents from an emulsion or aqueous solution containing higher molecular weight solutes. However, it has been surprisingly discovered that gels not only selectively remove water from macromolecular solutions but also from lipophilic fluid solutions.
Traditional separation techniques for dry cleaning solvent/water emulsions and/or mixtures typically involve distillation of all solvent-containing fluids, including those that do not require it. In this regard, distillation is used not only to remove impurities such as body soils from the post-use dry cleaning solvent, but is also used to separate solvent from water—a function that can be carried out in other ways. Distillation often involves high operating costs in the form of energy and equipment necessary to achieve the separation and, thus is undesirable in many instances, particularly when the equipment is within a consumer's home. Lastly, as noted, distillation is not necessary for all solvent-containing fluids arising from dry-cleaning. For example, evaporated solvent-water mixtures do not necessarily require distillation since they are substantially “impurity-free” and only require water-solvent separation operations.
Accordingly, the need remains for a cost effective, efficient, and safe separation method for lipophilic fluids and water, particularly when an emulsifier is present.